Wheel-tire.



No. 730,638. PATBNTED JUNE 9, 1903.-

D. Y E. GRIFFITHS. WHEEL TIRE.

APPLICATION FILED FEB. 14, .1903.

UNITED STATES Patented June 9, 1903. I

PATENT OFFICE.

DANIEL E. GRIFFITHS, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO JAMES B.COREY, OF PITTSBURG, PENNSYLVANIA.

WHEEL-TIRE.

SPECIFICATION forming part of Letters Patent N 0. 730,638, dated June 9,1903.

Application filed February 14, 1908. Serial No. 143,373. (No model.)

To aZZ whom it may concern.-

Be it known that I, DANIEL E. GRIFFITHS, a citizen of the United States,residing at Pittsburg, in the county of Allegheny and State ofPennsylvania, have invented certain new and useful ImprovementsinWVheel-Tirespf which the following is a specification, reference beinghad therein to the accompanying drawings, forming part of thisspecification, in which- Figure l is a view in side elevation of a wheelequipped with my improved tire. Fig. 2 is a plan view, partially insection, indicated by the line 11 II of Fig. 1. Fig. 3 is a similar viewshowing a modification. Fig. 4 is a perspective view showing the actionof the tire in turning off of a track-rail.

My invention refers to improvements in tires for wheels of vehicles; andit has for its object to provide a tire which will permit the wheel tobe turned off of a track-rail, thereby overcoming the slippage of theordinary tire, especially with heavy loads or in case of slippery rails.

Referring to the drawings, A represents the body portion of the tire,which is preferably made in one continuous circular piece or in astraight section formed into a circle and joined at the ends. The tireis fiat on its under side and adapted to fit upon the rim of the wheelin the usual manner, as indicated at 2. Upon its periphery the tire isformed by rolling or otherwise into two'tread elements a I), each ofwhich has an undulating contour consisting of closely adjacent roundedconvex peripheral projections 3 and intervening rounded concavedepressions 4. The convex extensions 3 of one set a are arrangedintermediate of the projections 3 of the other set Z) and opposite thedepressions therein, and vice versa, while the peripheral summits ofboth sets of projections conform to a common radius. As thus constructedand arranged the rolling weight is carried by the successivelycontacting projections, which being closely adjacent thus provide apractically continuous tread, approximating in action a smooth tire.Vhen the vehicle is driven 011 a track, as an ordinary street-car track,and turned off to one side, the depression on the outer side, which isopposite the inner bearing projection, (which at the moment rests 011the rail,) will allow for clearance of the rail-head and permit the nextadjacent projection to swing out over the rail-head, as clearly shown inFig. 4, so that it will then rest on the rail-head and the wheel willeasily ride over it.

\Vhile in the principal figures of the drawings I have shown both sidesof the tires as of the same form and while this is of advantage inpermitting the tires to be used interchangeably with either side out, itwill be observed that the operative or climbing portion of the tire willalways be 011 the outside. The inner portion may therefore be madesmooth, of the maximum height of the outer projections 3, as showninFig. 3, inasmuch as the purpose of such inner portion is to always holdthe outer depressed concave surface above the top of the rail-head, soas to permit the next oncoming projection to be swung out over it inturning. The entire tire may also be made in two pieces, either bothundulating or one (the outer) undulating and the other plain; but ifboth are made undulating care should be taken that in assembling them toprovide a complete tire that the projections and depressions arealternated, as already described.

My invention will be found to be of great advantage in overcoming thedifficulty of turning off of tracks with smooth tires, especially withheavy vehicles, while the rolling action of the Wheel is not interferedwith. It

.is very simple, cheap, and easily made and applied, while reducingfrictional wear.

Changes and variations of the projections and depressions or in otherdetails of construction may be made by the skilled mechanic; but allsuch are to be considered as within the scope of the following claims.

\Vhat I claim is' 1. A tire for vehicle-wheels having two series ofalternating peripheral projections and depressions meetingat the middleof thewheel, the projections and depressions of one side being oppositethedepressions and projections respectively ofthe other side,substantially as set forth.

2. A tire for vehicle-wheels having two series of alternating peripheralcontinuouslyrounded projections and depressions meeting at the middle ofthe wheel, the projections and ICO ries of alternate peripheralprojections and depressions extending atright angles to the edge acrossthe tire, the projections and de pressions of one side being oppositethe depressions and projections respectively of the other side,substantially as set forth.

In testimony whereof I affiX my signature in presence of two witnesses.

DANIEL E. GRIFFITHS.

Witnesses:

C. M. CLARKE, R. H. MOLARN.

